1. Technical Field
This disclosure relates to methods and apparatus for manufacturing hollow airfoils generally, and more particularly to a method and apparatus for providing support within an internal cavity of the airfoil during the manufacturing process.
2. Background Information
A gas turbine engine includes a fan section, a compressor section, a combustor and a turbine section disposed along an axially extending centerline. The fan section includes a plurality of rotor assemblies rotatable about the centerline, and at least one stator assembly. Each rotor assembly has a rotor disk and plurality of fan blades extending radially out from the disk. The fan blades are disposed within a gas path where they are operable to transfer energy to air passing therethrough, thus producing useful thrust. Each fan blade has an airfoil portion, and in most instances an inner platform as well. Fan blades that can be selectively mounted on the disk include a base (sometimes referred to as a “root”) that engages the disk for attachment purposes.
Some gas turbine fan blades (typically referred to as a “hollow fan blade”) have an internal cavity disposed within the airfoil section, which cavity is formed between a pressure side wall and a suction side wall, and a plurality of ribs extending between the walls. Typically, hollow fan blades are manufactured by joining a first portion of the airfoil together with a second portion of the airfoil. Welding is a known method of attachment. One of the problems associated with welding is that the airfoil portions can distort during the process and create misalignments between mating portions, thereby making it difficult to properly join the portions. This is particularly problematic in those instances where the mating parts cannot be visually inspected.